Donatella poses for Givenchy

Donatella Versace has helped out her friend Riccardo Tisci by starring in his new campaign.

It could be a first in fashion to see one designer appear in another's ads, but Donatella has thrown any rules out of the window by posing for Givenchy.

Both took to social media to excitedly reveal the news and the campaign image to fans. In the shared snap, Donatella and Riccardo appear pensive as they face in opposite directions, their profiles shown in black and white. Only their faces are visible, but Donatella appears to wear a black jacket and Riccardo a chequered shirt.

Riccardo, 40, has been head of Givenchy since 2005 and friends with Donatella, who turns 60 next month, for many years. Back in 2011 they appeared in a feature for Interview magazine, where she had a chance to quiz him on his work.

Donatella complimented his creations, mentioning how much she loved Cate Blanchett's Givenchy dress at the 2011 Oscars.

"Thank you so much. I’ll tell you, when I arrived here at Givenchy, there was a lot of confusion. Before me, there had been some great geniuses - John Galliano and Alexander McQueen are great masters. They marked history," Riccardo send in response.

"But when I came in after Julien Macdonald, it was also a bit of a mess, because not even I could understand what the true identity of Givenchy was. Everyone thinks that it’s only Audrey Hepburn, but there is a whole other world behind it. So in the end, I closed all the doors and didn’t let anyone in so I could find it for myself. I didn’t want to dress anyone in the beginning, no celebrities.

"Then, very slowly I started with one, two, like that. There are some celebrities whom we dress because they are part of the family. They are women I admire. I don’t care how famous she is, if she is at the movies or in a concert."